Methods of passivation to control oxygen content and reactivity of silicon-carbon composite materials

Abstract

Passivated silicon-carbon composite materials and related processes are disclosed that overcome the challenges for providing amorphous nano-sized silicon entrained within porous carbon. Compared to other, inferior materials and processes described in the prior art, the materials and processes disclosed herein find superior utility in various applications, including energy storage devices such as lithium ion batteries.

1 - 58 . (canceled) 
     
     
         59 . A hydrosilylation passivated silicon-carbon composite material, comprising:
 a. a porous carbon scaffold comprising a pore volume, wherein the pore volume comprises greater than 70% microporosity;   b. nano-sized silicon domains disposed within pores of the porous carbon scaffold, wherein a surface of the nano-sized silicon domains comprises Si—R bonds, wherein R comprises:
 i. an organic functional group comprising one or more of carbon, oxygen, nitrogen, and hydrogen; and, 
 ii. one or more optional halogen element; 
   c. a silicon content of 30% to 60% by weight;   d. a surface area of less than 30 m 2 /g;   e. a Z of less than 10, wherein Z=1.875×[(M1100−M)/M1100]×100, wherein M1100 is a mass of the passivated silicon-carbon composite material at 1100° C. and M is the minimum mass of the passivated silicon-carbon composite material between 800° C. and 1100° C. when the passivated silicon-carbon composite material is heated under air from about 25° C. to about 1100° C., as determined by thermogravimetric analysis; and   f. a φ of greater than or equal to 0.1, wherein φ=(Max peak height dQ/dV in Regime I)/(Max peak height dQ/dV in Regime III), wherein dQ/dV is measured in a half-cell coin cell, and Regime I is 0.8V-0.4V and Regime III is 0.15V-0V.   
     
     
         60 . The composite material of  claim 59 , wherein the nano-sized silicon domains comprise one or more layers of passivate silicon located below the terminally passivated silicon surface, and the layers of passivated silicon are silicon oxide layers. 
     
     
         61 . The composite material of  claim 59 , further comprising a Dv50 between 5 nm and 20 microns. 
     
     
         62 . The composite material of  claim 59 , wherein the hydrosilylation passivated silicon-carbon composite material gasses less than 0.005 mol/mol silicon/h in an aqueous suspension at 45° C. 
     
     
         63 . The composite material of  claim 59 , comprising a mol ratio of oxygen to silicon, wherein the mole ratio of oxygen to silicon increases less than 0.01 mol/mol/day when exposed to 25° C. in the presence of air. 
     
     
         64 . The composite of  claim 59 , wherein the passivated silicon-carbon composite comprises a surface area less than 10 m 2 /g. 
     
     
         65 . The passivated silicon-carbon composite of  claim 59 , wherein a mole ratio of oxygen to silicon is less than 0.5 mol/mol. 
     
     
         66 . The passivated silicon-carbon composite of  claim 65 , wherein the mole ratio of oxygen to silicon increases less than 0.01 mol/mol/day when exposed to 25° C. in the presence of air. 
     
     
         67 . The passivated silicon-carbon composite of  claim 65 , wherein the passivated silicon-carbon composite gasses less than 0.005 mol/mol silicon/h in an aqueous suspension at 45° C. 
     
     
         68 . A chemical vapor passivated silicon-carbon composite material, comprising:
 a. a porous carbon scaffold comprising a pore volume, wherein the pore volume comprises greater than 70% microporosity;   b. nano-sized silicon domains within pores of the porous carbon scaffold, wherein a surface of the nano-sized silicon domains comprises Si—H bonds; and   c. a carbonaceous layer at least partially covering the silicon domains, wherein the chemical vapor passivated silicon-carbon composite material comprises:
 i. a silicon content of 30% to 60% by weight; 
 ii. a surface area less than 30 m 2 /g; 
 iii. Z of less than 10, wherein Z=1.875×[(M1100−M)/M1100]×100%, wherein M1100 is a mass of the passivated silicon-carbon composite material at 1100° C. and M is the minimum mass of the passivated silicon-carbon composite material between 800° C. and 1100° C. when the passivated silicon-carbon composite material is heated under air from about 25° C. to about 1100° C., as determined by thermogravimetric analysis; and 
 iv. a φ of greater than or equal to 0.1, wherein φ=(Max peak height dQ/dV in Regime I)/(Max peak height dQ/dV in Regime III), wherein dQ/dV is measured in a half-cell coin cell, and Regime I is 0.8V-0.4V and Regime III is 0.15V-0V. 
   
     
     
         69 . The composite material of  claim 68 , wherein the nano-sized silicon domains comprise one or more layers of passivate silicon located below the terminally passivated silicon surface, and the layers of passivated silicon are silicon oxide layers. 
     
     
         70 . The composite material of  claim 68 , further comprising a Dv50 between 5 nm and 20 microns. 
     
     
         71 . The composite material of  claim 68 , wherein the chemical vapor passivated silicon-carbon composite material gasses less than 0.005 mol/mol silicon/h in an aqueous suspension at 45° C. 
     
     
         72 . The composite material of  claim 68 , comprising a mol ratio of oxygen to silicon, wherein the mole ratio of oxygen to silicon increases less than 0.01 mol/mol/day when exposed to 25° C. in the presence of air. 
     
     
         73 . The composite of  claim 68 , wherein the passivated silicon-carbon composite comprises a surface area less than 10 m 2 /g. 
     
     
         74 . The passivated silicon-carbon composite of  claim 68 , wherein a mole ratio of oxygen to silicon is less than 0.5 mol/mol. 
     
     
         75 . The passivated silicon-carbon composite of  claim 74 , wherein the mole ratio of oxygen to silicon increases less than 0.01 mol/mol/day when exposed to 25° C. in the presence of air. 
     
     
         76 . The passivated silicon-carbon composite of  claim 74 , wherein the passivated silicon-carbon composite gasses less than 0.005 mol/mol silicon/h in an aqueous suspension at 45° C.